FIG. 11 shows an example conventional linear guide apparatus. This linear guide apparatus includes a guide rail 100, a slider (also referred to a “bearing”) 200, and a plurality of rollers (rolling elements) 300. The guide rails 100 and the slider 200 are disposed so as to face with each other, and have therebetween rolling grooves 110 and 210, respectively, which constitute rolling channels for the rollers 300.
The slider 200 can be divided into a slider main body 201, end caps 202 fixed to both ends thereof, and side seals 203 further attached to both ends of the slider main body in a linear-motion direction (the lengthwise direction of the guide rail 1). The rolling grooves 210 are formed in the slider main body 201. The side seals 203 disposed at both ends of the linear motion direction of the slider 102 seals spaces between the slider 200 and the top face of the guide rail 100 and both side faces thereof.
The slider 200 also includes return channels 221 for the rollers 300, and turn-over channels 222 that cause respective return channels 221 and respective rolling channels to be communicated with each other. The return channels 221 are formed in the slider main body 201, while the turn-over channels 222 are formed in each end cap 202. Female screws 205 for attaching a table, etc., by means of screws are formed in the top face of the slider 200.
Attachment holes for a grease nipple 400 are formed in the side seal 203 and the end cap 202. A lubricant is introduced to an oil path of the end cap 202 through the grease nipple 400, so that the linear guide apparatus is lubricated. The side seals 203 and the end caps 202 are attached to the slider main body 201 by bolts 500. Attachment holes 120 for enabling attachment of the guide rail 100 to a mounting object like a base by means of bolts are formed in the guide rail 100.
According to this linear guide apparatus, a circulation channel for the rolling elements is formed with the rolling channel, the return channel, and the turn-over channel The rollers 300 circulate in the circulation channel, thereby allowing any one of the guide rail 100 and the slider 200 to take a linear motion with respect to the other.
An example conventional side seal for such a linear guide apparatus has a metal plate and a base for a rubber-made seal member fixed on the metal holder plate. The lip of the seal member is brought into contact with the top face of the guide rail and both side faces thereof when in use.
Patent Document 1 discloses a technology that the holder plate (a casing) of the side seal and the seal member (a seal) with a lip (a sealing lip) are formed of different members, and a scraper is disposed so as to face the external face of the guide rail with a clearance from such an external face at the opposite side of the holder plate of the seal member. The holder plate and the seal are engaged with each other by fitting of a protrusion and a recess. According to such a side seal, relatively large foreign materials are removed by the scraper at first, and thus the sealing lip can have a longer life and an improved action.
Patent Document 2 discloses a side seal (a scraper) including two seal members having lips (sealing lips) inclined in opposite directions to each other, a piece of support plate that supports those seal members, and a housing having recesses that receive respective bases of the seal members and the support plate.
According to such a side seal, the seal members can be replaced without detaching the whole slider (the guide carriage) from the guiding rail (the guide rail) by employing the above-explained structure. The support plate employs a structure that can support the side seal without deteriorating the function as the side seal in both cases in which the support plate supports the two side seals and in which the support plate supports only one seal member formed of a flexible material.
Patent Document 3 discloses a side seal including an integrated type seal member which has a lip (a slider-side lip) directed to the slider main body and another lip (dust-side lip) directed to the opposite side and which is fixed on a metal holder plate. This side seal has both slider-side lip and dust-side lip, thereby improving both sealing performance and dust-proof performance. Moreover, Patent Document 3 discloses that a cover (a protector) for protecting the side seal from a high temperature, and foreign materials with high hardness are disposed at the outside of the side seal. A clearance is provided between the cover and the dust-side lip, so as to suppress the increase in a sealing frictional force caused by the actuation of the slider.